This acquisition is for the maintenance of an international bone marrow transplant registry (IBMTR). The purpose of the IBMTR is to pool data acquired from national and international transplant centers and to analyze this data in a disciplined and thoroughly tested manner. To date, a data base of over 3,000 recipients exists with over 1,000 accruing during the past 18 months. The increased frequency of bone marrow transplants supports the need for the IBMTR's continuing acquisition and analysis of the rapidly expanding data base. The data and results acquired through this acquisition shall potentially improve the prognosis for individuals at risk because of congenital or other cause of immunodeficiencies. These results shall assist in the development and production of monoclonal antibody therapy used to abrogate graft versus host disease and provide a more comprehensive data base upon which to design more efficient procedures for allogeneic bone marrow transplantation.